The present invention relates to a coupling for use with pressurized fluid systems. More particularly, the present invention relates to an externally threaded quick connect coupling having integral fluid pressure assisted seal.
Current methods for attaching fluid lines and plugging threaded fluid ports generally include a sealing arrangement requiring a wrenching operation to ensure an adequate seal. The sealing arrangement typically involves metal interference of mating parts, sealants, or elastomeric seals. The wrenching operation is required in order to complete the sealing process, or at least prevent the sealing arrangement from being overcome by fluid pressure in the fluid ports. This is time consuming and often cumbersome to accomplish.
Several attempts have been made at developing quick connect couplings utilizing fluid pressure actuated seals. See for example, U.S. Pat. Nos. 4,345,783; 4,375,297; 4,527,817; and 4,543,995. However, these couplings, while enabling a quick connection to occur, are rather cumbersome and have a relatively large coupling body making them difficult, if not impossible, to use in difficult to get at areas, or where there is reduced space availability.
Additionally, the above mentioned first three patents utilize a separate actuating fluid port for delivery of an actuating fluid which adds to their bulkiness and complicated nature. Additionally, the above mentioned fourth patent, which utilizes mechnical jaws pressed together in one position and spread apart in another position, is more complicated than that of the present invention.
U.S. Pat. No. 3,291,442 discloses a rather complicated gas or vacuum-operated coupling including a sleeve and plug slidably mounted on/in the coupling body and which are moved by gas pressure.
The present invention solves these and many other problems associated with currently available coupling devices.